Glyceryl esters are a widely known class of compounds. They are naturally occurring materials in both the plant and animal world. The natural occurring Glyceryl esters are referred to as triglycerides and are the result of very specific enzymes used by living systems to get highly specialized molecules. These include olive oil, soybean oil and coconut oil. These esters don not contain any fatty groups above C22. An essential element of the present invention is high molecular weight high melting point fatty acids derived from ethylene, which is subsequently oxidized using nickel catalyst. It is this high molecular weight fatty acid in a random molecule with lower melt point fatty acids that allows for control of the properties like hardness, spread on the skin and aesthetics.
The variation in alkyl chain length in naturally occurring products is quite small. Since the triglycerides made in nature are designed as an energy source for the plant or animal, the carbon chain variation is quite small, generally at 18 carbon atoms.
Triglycerides are natural products that are provided to plants and animals as a storage molecule for energy to be used by the plant or animal when needed.
Typical glyceryl esters are disclosed in U.S. Pat. No. 7,550,623, incorporated herein by reference. The invention teaches “The present invention provides a liquid ester composition which is obtained by esterifying a branched isostearic acid such as 2-(1,3,3-trimethyl)butyl-5,7,7-trimethyl octanoic acid with dipentaerythritol, and said liquid ester composition having a viscosity at 25.degree. C. of 100,000 to 2,000,000 mPas; hydroxyl value of 10 to 160; and cloud point of less than 5° C.”
Fats occur naturally in food and play a significant role in human nutrition. Fats are used to store energy in the body, insulate body tissues, cushion internal organs, and transport fat-soluble vitamins in the blood.
Fats are the most prevalent class of compounds (in living systems) referred to as lipids. Lipids are cellular compounds that are insoluble in water. Fats are soft, low-melting solids, with a density less than that of water. They have a greasy feel and are slippery. Fats and closely related oils are mixtures of compounds consisting of fatty acids combined with glycerol (commonly known as glycerin) via ester linkages. Fatty acids are long, straight chain carboxylic acids. A fat (or oil) is formed when three fatty acid molecules react with a glycerol molecule to yield a triglyceride (and three water molecules). Fats in the body are transported and stored as triglycerides.
The compounds of the present invention are glyceryl esters that contain both high melting groups (not naturally occurring) and lower melting point groups in the same molecule. The placement of these groups in the same molecule as will become clear from reading the specification of this invention, results in a unique ability to alter a combination of properties, including hardness, rheology and skin aesthetics. It is very important to note that each of the hydroxyl groups on the glycerin are randomly either have a high melting or low melting group thereon. This is a direct consequence of the fact that from a reactivity point of view each hydroxyl group is as reactive as each other on glycerin (no regiospecificity) and each carboxyl on each acid is equally reactive, resulting in a totally random glyceryl ester. This is the exact opposite of what happens in nature, where each group is carefully controlled using enzyme systems possessed by the living plant or animal making such esters biologically. This random pattern is critical to the functionality making the resulting mixed ester very unlikely to form highly organized crystalline waxes, rather forming amphorous solids and butter like products.
We have determined that the difference in melting point of at least 20° C. is a critical factor in the present invention. When the range of melt point is this far apart (i.e. the difference between the high melting point acid and the low melting point acid,) the resulting product has a softness that confers a butter like consistency. Without wanting to be held to one particular explanation, we believe that when the difference is that great a fractional solidification occurs upon cooling resulting in an appreciable amount of time where there are both solid and liquid domains in the cooling wax. This lack of uniformity results in the “disrupted wax” being formed. In a preferred embodiment, the lower melting acid is liquid at ambient temperature and never becomes solid under ambient temperatures, which is the temperature of application for personal care products.